FDA adds blood clot warning to testosterone products

All testosterone-containing treatments marketed in the US will need to carry a warning about the risk of blood clot following new guidance from the FDA.

Testosterone products are generally used to replace low levels of natural testosterone to help improve energy levels and sex drive in aging men.

These therapies already carry a warning that the risk of venous blood clots as a consequence of polycythemia, an increased number of red blood cells in the body.

However, there have been several reports noting cases of venous blood clot that have been unrelated to polycythemia, causing the FDA to add a more general warning to all testosterone products about the risk of serious venous thromboembolism events, including deep vein thrombosis and pulmonary embolism.

The FDA said it had notified healthcare professionals and medical care organisations, and that any adverse events or side effects should be reported to the regulators' MedWatch Safety Information and Adverse Event Reporting Program.

Venous thromboembolism is not the only safety concern currently under investigation in testosterone treatments; there is an ongoing FDA evaluation into the risk of stroke, heart attack and death in patients on these medications.

In its statement, the FDA said it is “currently evaluating the potential risk of these cardiovascular events, which are related to blood clots in the arteries”.

Testosterone treatments are also a concern in Europe where the European Medicines Agency (EMA) announced earlier this year it was to investigate their safety.

The review was triggered by the Estonian medicines agency after concerns were raised about the side effects of these medicines on the heart.